This invention relates to devices and methods for the controlled release of small quantities of drugs and other molecules from reservoirs, the controlled exposure of microsized secondary devices located in reservoirs, or combinations thereof.
U.S. Pat. No. 5,797,898, No. 6,123,861, No. 6,527,762, No. 6,491,666, and No. 6,551,838 disclose devices having an array of multiple, discrete reservoirs which contain small quantities of drugs or other molecules or secondary devices for controlled release. For example, the device can be implanted for the controlled administration of drug to a patient in need thereof. Various release mechanisms are described. In one embodiment, each reservoir has a reservoir cap positioned on the reservoir over the molecules, so that the molecules are released from the device by diffusion through or upon disintegration of the reservoir cap. The reservoir caps can be controllably disintegrated to release the molecules from the reservoirs at selected times. In one embodiment, which is disclosed in U.S. Pat. No. 5,797,898, the reservoir cap is a metal film, which functions as an anode, and an electric potential is applied between the anode and a cathode to cause the metal film to oxidize and disintegrate. It would be advantageous to provide additional mechanisms for releasing the drug molecules from the reservoirs, particularly active release mechanisms that can provide an enhanced rate of release of the molecules from the reservoirs, thereby speeding the rate the released molecules diffuse into the target fluid, e.g., at the site of implantation of the device.
U.S. Pat. No. 6,123,861 discloses microchip reservoir devices made using a process that requires several steps including a series of MEMS processing steps. It would be desirable to provide new types of reservoir array devices and methods of manufacture therefor, particularly where simplified methods can be used to produce a complete and hermetically sealed micro-reservoir.